All properties lose heat through their windows. But, energy-efficient glazing keeps your home warmer and quieter as well as reducing your energy bills.

Double-glazed windows consist of two panes of glass with a gap in between, usually about 16mm, to create an insulating barrier that keeps heat in. This is sometimes filled with gas. Double glazing has many benefits over single glazing (where there’s just one pane of glass and no air layer):

Heightens security – double-glazed glass is more difficult to break than single glazing.

According to the Energy Saving Trust, if you were to replace all of the windows in a three-bedroom, semi-detached house, going from single-glazed windows to double glazing, you’d save between £75 and £110 per year, depending on the window energy rating.

Key features to look out for:

Glass – The most energy-efficient type for double glazing is low emissivity (Low-E) glass. This often has an invisible coating of metal oxide, normally on one of the internal panes. This lets in light and heat but cuts the amount of heat that can get out.

Gaps between the glass – Very efficient windows use gases such as argon in the gap between the sheets of glass.

Pane spacers – These are set around the inside edges to keep the two panes of glass apart. For maximum efficiency, look for pane spacers containing little or no metal – often known as ‘warm edge’ spacers.

All Norscot windows and doors are double glazed as standard and feature Low-E glass, argon gas in the gap between the sheets of glass and ‘warm edge’ Super Spacer to keep the two panes of glass apart.